Hi Team

We have an 82 Indy Pace car with no original running gear which is from the previous owner. She had a 4th gen rear diff which I have just swapped out to a 3.27 posi disc brake rear. Unfortunately at 60mph she’s sitting at 2800rpm! Not good for economy or wear & tear.
As above she currently has a TH350 trans but I have since been offered a fully reconditioned TH700R4 trans which I understand has a torque converter lockup. Our car is only ever going to be a cruiser.

My question is will this give us the significant better top end highway gearing & economy?
secondly, what do I need to do to change from the TH350 to the TH700R4? What wiring is required for the torque converter lockup?

 

The overdrive ratio—0.70 for the 700-R4, 0.67 for the 200-4R—is virtually identical, but the 200-4R offers a better ratio spread (2.74, 1.57, 1:1, 0.67) that reduces rpm drops during gear changes.

 

........unless the OP means a TH200c.......which is a light duty version of the TH350, mounts on the same x-member, and has lockup.

 

The 2004R has the overdrive. The TH200 or TH200C is still a three speed, and does not have overdrive. If you are going to use the 2004R. Then you will need to get the torque converter lockup kit from Painless for the 2004R.

 

Since originally posting this, we realised the trans offered was a TH200c, not the R4. I have since secured a TH700R4 to fit to our car.